Rutgers’ coaching scandal spiraled deeper Friday, bringing down the popular athletic director and a school vice president while donors threatened to cut off their contributions to New Jersey’s largest public university.

The day of mounting troubles for the school began with Athletic Director Tim Pernetti resigning over his failure to immediately fire coach Mike Rice, who was caught on video hitting, kicking and taunting players with anti-gay slurs at practice.

The video was shown Tuesday on ESPN, prompting outrage nationwide and on campus.

49ers’ Anthony Davis gets 5-year extension

SAN FRANCISCO

Right tackle Anthony Davis has signed a five-year contract extension with the San Francisco 49ers.

The deal is worth more than $37 million, with $17 million guaranteed.

The 23-year-old tackle has started 16 games in each of his first three years. He helped the 49ers win consecutive NFC West titles and reach the Super Bowl last season, a 34-31 loss to Baltimore.

Davis played at Rutgers and was the 11th overall pick of the 2010 draft.

Arizona Cardinals sign CB McCann, S Taylor

TEMPE, Ariz.

The Arizona Cardinals have signed cornerback Bryan McCann and safety Curtis Taylor to one-year contracts.

McCann played in eight games for Miami last season. In 2011, he played in 12 games with Dallas, Baltimore and Oakland. He began with the Cowboys as an undrafted rookie free agent in 2010.

Taylor has played in 12 games for San Francisco in his career. He was on the 49ers’ practice squad last postseason after signing with the team on Dec. 26.

Williams sisters win their way into semis

CHARLESTON, S.C.

Top-ranked Serena Williams ended a long and successful day for the Williams family as she and sister Venus both won twice Friday to reach the Family Circle Cup semifinals and set up their first sibling showdown since 2009.

The Oakland Raiders have waived linebacker Rolando McClain less than three years after drafting him eighth overall.

McClain is the third player drafted in the top 10 by late owner Al Davis to be let go so far this offseason by second-year general manager Reggie McKenzie. Defensive back Michael Huff (seventh pick in 2006) and receiver Darrius Heyward-Bey (seventh pick in ‘09) were cut last month.

Oakland has only two of its own first-round picks on the roster in running back Darren McFadden and kicker Sebastian Janikowski as McKenzie overhauls the roster.